package com.mx.ai.sports.common.utils;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONArray;
import com.alibaba.fastjson.JSONObject;
import com.auth0.jwk.Jwk;
import com.mx.ai.sports.common.exception.AiSportsException;
import io.jsonwebtoken.*;
import org.apache.commons.codec.binary.Base64;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.web.client.RestTemplate;

import java.security.PublicKey;

public class AppleUtil {

    private static final Logger logger = LoggerFactory.getLogger(AppleUtil.class);

    /**
     * 获取苹果的公钥
     * @return
     * @throws Exception
     */
    private static JSONArray getAuthKeys() throws Exception {
        String url = "https://appleid.apple.com/auth/keys";
        RestTemplate restTemplate = new RestTemplate();
        JSONObject json = restTemplate.getForObject(url,JSONObject.class);
        JSONArray arr = json.getJSONArray("keys");
        return arr;
    }

    public static Boolean verify(String jwt) throws  Exception{
        JSONArray arr = getAuthKeys();
        if(arr == null){
            return false;
        }
        JSONObject authKey = null;

        //先取苹果第一个key进行校验
        authKey = JSONObject.parseObject(JSON.toJSONString(arr.get(0)));
        if(verifyExc(jwt, authKey)){
            return true;
        }else{
            //再取第二个key校验
            authKey = JSONObject.parseObject(JSON.toJSONString(arr.get(1)));
            return verifyExc(jwt, authKey);
        }

    }

    /**
     * 对前端传来的identityToken进行验证
     * @param jwt 对应前端传来的 identityToken
     * @param authKey 苹果的公钥 authKey
     * @return
     * @throws Exception
     */
    public static Boolean verifyExc(String jwt, JSONObject authKey) throws Exception {

        Jwk jwa = Jwk.fromValues(authKey);
        PublicKey publicKey = jwa.getPublicKey();

        String aud = "";
        String sub = "";
        if (jwt.split("\\.").length > 1) {
            String claim = new String(Base64.decodeBase64(jwt.split("\\.")[1]));
            aud = JSONObject.parseObject(claim).get("aud").toString();
            sub = JSONObject.parseObject(claim).get("sub").toString();
        }
        JwtParser jwtParser = Jwts.parser().setSigningKey(publicKey);
        jwtParser.requireIssuer("https://appleid.apple.com");
        jwtParser.requireAudience(aud);
        jwtParser.requireSubject(sub);

        return true;

//        try {
//            Jws<Claims> claim = jwtParser.parseClaimsJws(jwt);
//            if (claim != null && claim.getBody().containsKey("auth_time")) {
//                System.out.println(claim);
//                return true;
//            }
//            return false;
//        } catch (ExpiredJwtException e) {
//            logger.error("apple identityToken expired", e);
//            return false;
//        } catch (Exception e) {
//            logger.error("apple identityToken illegal", e);
//            return false;
//        }
    }



    /**
     * 对前端传来的JWT字符串identityToken的第二部分进行解码
     * 主要获取其中的aud和sub，aud大概对应ios前端的包名，sub大概对应当前用户的授权的openID
     * @param identityToken
     * @return  {"aud":"com.xkj.****","sub":"000***.8da764d3f9e34d2183e8da08a1057***.0***","c_hash":"UsKAuEoI-****","email_verified":"true","auth_time":1574673481,"iss":"https://appleid.apple.com","exp":1574674081,"iat":1574673481,"email":"****@qq.com"}
     */
    public static JSONObject parserIdentityToken(String identityToken){
        String[] arr = identityToken.split("\\.");
        String decode = new String (Base64.decodeBase64(arr[1]));
        String substring = decode.substring(0, decode.indexOf("}")+1);
        JSONObject jsonObject = JSON.parseObject(substring);
        return  jsonObject;
    }


    /**
     * 获取appleId
     *
     * @param identityToken identityToken
     * @return
     */
    public static String getAppleId(String identityToken) {
        try {
            //验证identityToken
            if (!AppleUtil.verify(identityToken)) {
                throw new AiSportsException("授权验证失败!");
            }
            //对identityToken解码
            JSONObject json = AppleUtil.parserIdentityToken(identityToken);
            if (json == null) {
                throw new AiSportsException("授权解码失败!");
            }

            return json.getString("sub");
        } catch (Exception e) {
            e.printStackTrace();
            throw new AiSportsException("系统错误!");
        }
    }
}
